We report calculations of valence levels in quasi one-dimensional semiconductor heterastructures. Subbend mixing is considered and the subband dispersions along the wire-axis direction are calculated for GaAsl'Ga(A1)A.s quantum wires. In the last years some progress has been achieved in reducing the sizes of semiconductor heterostructures. Quasi uni-dimensionel semimnductors'-3 have bean obtained via sophisticated growth, etching and cutting techniques. In i&s1 unidimensional structures the carrier motion along two directions (z and x) is bound while it is free along the third one (y). The carrier mobility has baen estimated to be enhanced over the bulk and two-dimensional values in the Electric Quantum Limit*due to the reduction of the available phase space for the scattering events On the other hand, it is not clear that the assumption underlying the predicted mobility enhancement, which IS that the carrier wavefunctions are spatially extended, can be reconcilied with the general statement that all states are spatially localized In quasi uni-dimensional materials. Recently, some new types of quasi-unidimensional semiconductor structures have been theoretically proposed. Chang et al' studied a non-rigid quest uni-dimensional structure which is obtained by converting one side of the potential barrier of an asymmetric quantum well into a periodically indented potential. Laux and Stern' performed a self-consistent calculation for e narrow gate Si-SiO, MOSFET, and Lai and Des